In the field of microfabrication represented by the manufacture of integrated circuit devices, lithographic technology enabling microfabrication with a line width of about 200 nm or less using an ArF excimer laser (wavelength: 193 nm), F2 excimer laser (wavelength: 157 nm), and the like has been demanded in order to achieve higher integration in recent years. As a radiation-sensitive resin composition applicable to the excimer laser radiation, a number of chemically-amplified radiation-sensitive compositions utilizing a chemical amplification effect between a component having an acid-labile functional group and an acid generator, a component generating an acid upon irradiation, have been proposed.
For example, a chemically-amplified positive-tone resist composition comprising a resin possessing alkali-solubility protected by a 2-alkyl-2-adamantyl group or 1-adamantyl-1-alkyladamantyl group, being insoluble or scarcely soluble in alkali by itself, but becoming alkali-soluble by the action of an acid, and a specific sulfonium salt acid generator (Japanese Patent Application Laid-open No. 2002-156750), a polymer for photoresist prepared by ternary copolymerization of a specific substrate-adhesive alicyclic ester, an acid-labile ester having a specific alicyclic skeleton, and, as a third component, a specific alicyclic ester having a polarity between the above first component and the second component (Japanese Patent Application Laid-open No. 2002-145955), a resin which contains three types of monomer units of specific structures having an alicyclic skeleton at a specific ratio (Japanese Patent Application Laid-open No. 2002-201232), and the like have been known.
However, to achieve a higher degree of integration in the field of semiconductor, a radiation-sensitive resin composition used as a resist is required to possess more excellent resolution. In producing more detailed patterns, reproducibility of raw materials that produce fluctuations in the product properties between manufacturing lots is demanded. In addition, along with the progress of microfabrication there are a number of cases in which a minor defect during development results in a fatal defect in the design of devices. As a countermeasure, in addition to the effort for increasing a process margin such as increasing resolution as a resist and radiation dose-dependency, promoting solubility of the resist in a solvent is regarded as an urgent subject of development, since minute defects produced during development are supposed to originate from the resin which is a component forming the resist.